BREAKING: releasing v1.0.0, adopt Typer as main frame

[RyoNakagami]

Summary

• This PR introduces a complete refactor of the yamlcli command-line interface using Typer, replacing the previous argparse-based implementation.
• It consolidates entry points, ensures consistent error handling, and adds a version flag while improving overall code organization.

Related Issue

• Closes / References: #IssueNumber

Type of Change

• Bug fix
• New feature
• Refactoring / Code cleanup
• Documentation update
• Other:

Description

• Migrated CLI implementation from argparse to Typer, enabling improved UX, clearer commands, and standardized exit/error handling.
• Introduced a single main command converter under the yamlcli CLI app, aligning with modern Python CLI practices.
• Added --version / -v flag with callback logic, providing version and Python information.
• Improved file existence checks, mutually exclusive option handling, and exception messages.
• Refactored imports and moved conversion logic to yamlcli_core and version handling to library/version.
• Removed the standalone main.py and replaced it with a clean Typer-based entry point via cli.py.

Changes Made

New Modules / Classes

• Introduced yamlcli.library.version for centralized version storage.
• Confirmed architecture using yamlcli.yamlcli_core for conversion logic.

Moved / Refactored

• Fully replaced argparse CLI (main.py) with Typer-powered cli.py.
• Consolidated entry points: both main() and __main__ now invoke app().

Enhanced / Fixed

• Improved YAML/JSON error handling using Typer's Exit mechanism.
• Better UX for incorrect flag combinations: explicit message and exit code 1.
• Added robust version display callback printing yamlcli + Python version.
• Ensured consistency between CLI calls and internal function API.

Removed / Deprecated

• Removed the argparse-based CLI system (main.py).
• Removed redundant path checks and exception duplication from previous implementation.

Additional Notes

• The new CLI is fully compatible with CliRunner for pytest, eliminating issues caused by runpy in earlier tests.
• This PR prepares the codebase for future subcommands (e.g., validation utilities, formatting, schema checks).
• No breaking changes for end users, except improved flag requirements.

---

Tests

Unit Tests

• New unit tests added based on CliRunner.
• Tests updated from previous argparse assumptions.
• All unit tests pass locally.

% uv run pytest --tb=no                              
================================ test session starts =================================
platform linux -- Python 3.13.7, pytest-8.4.2, pluggy-1.6.0
rootdir: .../yamlcli
configfile: pyproject.toml
testpaths: tests
plugins: cov-7.0.0
collected 15 items                                                                   

tests/test_coremodule.py .......                                               [ 46%]
tests/test_yamlcli.py ........                                                 [100%]

=================================== tests coverage ===================================
__________________ coverage: platform linux, python 3.13.7-final-0 ___________________

Name                                 Stmts   Miss  Cover   Missing
------------------------------------------------------------------
src/yamlcli/__init__.py                  2      0   100%
src/yamlcli/cli.py                      38     11    71%   24-26, 64-70, 74, 77
src/yamlcli/library/__init__.py          0      0   100%
src/yamlcli/library/helper_func.py      21     15    29%   19-37
src/yamlcli/library/version.py           2      0   100%
src/yamlcli/yamlcli_core.py             17      0   100%
------------------------------------------------------------------
TOTAL                                   80     26    68%

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Checklist

• Code follows Python style guidelines.
• Docstrings updated for Typer-based CLI.
• Type hints preserved / updated where applicable.
• Logging and error handling consistent with Typer expectations.
• Dependencies checked (PyYAML, Typer).
• Breaking changes documented.
• Related issue referenced in this PR.